The Hong Kong Observatory (HKO) operates an automatic upper-air sounding system (Figure 1) which regularly releases a weather balloon carrying a radiosonde that measures and computes wind speed and direction, temperature, humidity, pressure, etc. at various heights of the atmosphere, providing indispensable data for weather forecasting.  The automatic upper-air sounding system, with a size close to that of a standard container, is located at the King's Park Meteorological Station.

To meet operational and development needs, HKO acquired a portable upper-air sounding system (PUPAS) in late 2014.  PUPAS comprises a small receiver, a processor, a sonde checker, antennas, etc.  The above components can essentially be fitted inside a couple of suitcases (Figures 2 and 3).  The system is easily transportable by one or two persons to collect meteorological data (Figure 4)  at different locations or even on board of a ship, thus enhancing the mobility and the application of upper-air sounding.